The present invention relates to a method for staining corneocytes as well as a method for preparing corneocytes specimen which can provide useful information for analysis of skin condition and appropriate selection of cosmetic products.
The present invention also relates to a skin analysis system which can provide useful information for analysis of skin condition and appropriate selection of cosmetic products.
Skin conditions may constantly change depending on variable factors including seasonal changes, physical conditions, skin treatment (e.g., application of cosmetic products) or the like. It is thus very important to select an appropriate cosmetic product according to such variable factors in order to prevent aging or keep skin in a good condition. For this purpose, methods for objectively and scientifically analyze skin type and/or condition have been developed. One example of such method involves collecting corneocytes from, for example, the surface of face using an adhesive tape or disc, staining the corneocytes, and analysis skin type and condition using as indicators various factors such as the arrangement regularity of the corneocytes, a shape or size of a horny cell (corneocyte), a roughness of the surface of horny stratum (keratinized layer), and the presence or absence of a nucleus in the horny cell. In such analysis, a staining method using gentian violet and brilliant green has been used since it can preferably provide a high contrast between cytoplasm and its background and thus confirm both the shape of individual corneocytes and the presence or absence of a nucleus in each horny cell. This method, however, requires a relatively longer period of time for the staining step and thus cannot immediately provide data for instant analysis (e.g., a personal consultation in store). Therefore, conventional methods for selecting cosmetic products based on the analysis of skin using as an indicator the shape of horny cell took several days until it could provide cosmetic samples after skin analysis, which disadvantageously produced a time lag. Although the amount of dye can be increased in such a case, it may yet take ten minutes or more for both gentian violet and brilliant green to stain cells even when their maximal water-solubility limits (gentian violet=1%, brilliant green=0.5%) are used. Therefore, conventional method still had a disadvantage in terms of staining time. Conventionally, organic solvents have not been used in such staining process since they may reduce staining-specificity or cause degeneration or alteration of cells. Accordingly, a method for staining a horny cell has not been known yet in which a sample containing corneocytes obtained by stripping off from a skin using an adhesive material (e.g., a stripper) is stained wherein a stain solution used in the staining step comprises a water-miscible organic solvent.
Generally, a stained horny cell sample may be mounted to obtain uniform refractive index through the entire sample. Balsam and ultraviolet-curing resins have conventionally been used for mountion. However, those mounting materials are not preferable since they may often cause color running, which may result in a significant error in automatic computation of, for example, the size of cell by binarization (by using a binary image of the corneocytes). Moreover, an adhesive tape cannot be used to obtain corneocytes since the adhesive or tape component thereof may be decomposed by the organic solvent used for mountion. For quick analysis of corneocytes in, for example, a personal consultation at a customer desk as described above, automatic computation of the size of horny cell by using the binary image of the horny cell is inevitable and thus a solution to such regarding color running problem has strongly been demanded. Oil and fat constituent and/or composition that is liquid at 1 atm, 25° C. has not been used for such mountion. This is because that it is difficult to preserve such a liquid mounting agent for 1 month or more and that such constituents or compositions have never been used for mountion so far. Accordingly, it is a novel finding that, by using such mounting agents, a corneocytes sample can be prepared which allows for an automatic calculation of the size of a horny cell by using the binary image of the corneocytes with little or no color running.
Skin conditions may constantly change depending on variable factors including seasonal changes, physical conditions, skin treatment (e.g., application of cosmetic products) or the like. It is thus very important to select an appropriate cosmetic product according to such variable factors in order to prevent aging or keep skin in a good condition. For this purpose, methods for objectively and scientifically analyze skin type and/or condition have been developed.
In order to select cosmetic products suitable for a particular customer, for example, conventional methods involved collecting corneocytes from, for example, the surface of face using an adhesive tape or disc with adhesive material, staining the corneocytes, and analysis skin type and condition using as indicators various factors such as the size of horny cell, the roughness of the surface of horny stratum (keratinized layer), and the presence or absence of a nucleus in the horny cell.
In such analysis, a staining method using gentian violet and brilliant green has been used since it can preferably provide a high contrast between cytoplasm and its background and thus confirm both the shape of individual corneocytes and the presence or absence of a nucleus in each horny cell.
This method, however, requires a relatively longer period of time for the staining step and thus cannot immediately provide data for instant analysis (e.g., a personal consultation in store). Therefore, conventional methods for selecting cosmetic products based on the analysis of skin using as an indicator the shape of horny cell took several days until it could provide cosmetic samples after skin analysis, which disadvantageously produced a time lag.
Therefore, no sales method has been introduced which can complete, within a day (or rather instantly), the whole process comprising analysis the skin of a customer at a store counter and recommending the customer a suitable trial cosmetic kit based on the analysis results so that the customer can purchase and try the kit and then select and purchase a full-size cosmetic product or products of the same version contained in the trial kit if he/she likes it or them.